The present invention is directed toward refrigeration and heating systems to be used in the food service industry and more particularly, toward serving pans and the like which are maintained at a low or a high temperature for prolonged periods of time and that are cooled or heated uniformly.
A problem facing many businesses in the food industry is the inability to maintain the temperature of foods meant to be kept cold or, particularly in a salad bar type of setting or in other settings where it may be necessary to keep foods chilled for extended periods of time after they have been removed from normal refrigeration facilities. Particularly difficult is the inability to maintain cold temperatures at the upper level of the foods which is require by the health authorities. That is, while it is normally too difficult to maintain salad or the like located near the bottom of a serving pan at a relatively cold temperature, it is difficult to maintain salad or a similar food at the top of the pan at an equally cold temperature.
In one type of salad bar arrangement, for example, shallow pans are placed within wells of a cabinet or service counter. The crocks or containers of food or food itself is then placed within the pans and crushed ice is then placed around the containers or the food. Alternatively, the ice may be placed within the pans first and then the containers may be placed in the ice. A problem with this type of arrangement is that it is difficult to maintain a suitable temperature for the food. That is, as the ice melts, it is necessary to continuously refill the pans with ice in order to maintain an appropriate temperature. This type of refrigeration system also requires constant supervision and maintenance.
Another typical salad bar has a refrigeration coil under the pans holding the crocks or containers of food or the food. Again, the problem with this type of system is that it is difficult to maintain a suitable temperature. That is, the food either freezes if it directly overlies a refrigeration coil or becomes too warm. Furthermore, the cooling tends not to be uniformly distributed to all of the food or containers particularly near the top of the pan. In these types of arrangements, in order to lower the temperature sufficiently near the top of the pan, the refrigeration coils must be so cold that food at the bottom of the pan which may be in close proximity to the coils freezes or deteriorates as a result of the very cold temperature.
U.S. Pat. No. 5,247,807 to Jarman et al. discloses a refrigerated condiments container which can be used in a salad bar. The container rests within a chamber which has refrigeration coils. The problem with this system, however, is that it is difficult to maintain a suitable temperature for the food. Also, the containers are not cooled uniformly, therefore the food within the containers is not kept cold with uniformity.
U.S. Pat. No. 4,989,419 to Brando et al. discloses a food service tray having a top tray and a bottom tray with a container being held within a hollow member formed in the top tray. The top tray and bottom tray form a chamber therebetween which is filled with a gel in order to keep the container chilled for an extended period of time. The problem with this type of system is that the use of gel still does not allow the food to be maintained at a low enough temperature as there is no way of continuously refrigerating the gel.